Electropneumatic sound-box.



C. STILLE. ELEGTROPNEUMATIC SOUND BOX. AIILHATION run; Arum 1,132,404, Patented Mar. 16, 1915 1722/01/20). Wzlneun. QYwbML U W 6 y 3% UNITED STATES PATENT OFFICE.

CURT STILIiE, OF ZEHLENDORF-WVEST, NEAR BERLIN, GERMANY.

ELECTROPNEUMATIC SOUND-BOX.

Application filed April 24, 1913.

To all 'm/w/n, it may concern:

lle it known that 1, Cum Svnmn. doctor of philosophy, of Zehlendorf-ll'est. a subject of the King of Prussia. and whose postoll'ice address is 4/5 lliilowstrasse, Zehlen dorf-lVest, near Berlin, Kingdom of Prussia, erman Empire, have invented a new and useful I ]lectropneumat-ic Sound-Box, of which the following is a specifi -ation.

This invention relates to an electro-pneumatic sound box, that is to say a sound box in which air is forced from a pressure res e1 voir or through tans and the like, through the box. and in which there is provided a grating, the openings ot' which are regutated bv an electro-magnet which is sup plied with telephone current or the like.

In the accompanying drawings one form of this improved sound box is shown by way ol example, in which Figure l is a diagrammatic view of the arrangement ol the said box, and Figs. 2 and 31 are views of details.

The box I) is provided with an opening ll tor the sound, and with an outlet. opening In the center there is arranged a diaphragm l provided with longitudinal slits a, which in Fig. 1 can only be seen in section. while in Fig. 3 they are drawn to a larger scale. Above the diaphragm disk I which may consist of brass or the like, there arranged the small plate 2!! which is provided with slits s which correspond to the slits a. The aforesaid plate (is adapted to move along bars and is held in suspension by the adjustable springs I. To the plate m there is secured a knee-shaped piece or bend K: which terminates in the armature (t. ()pposite this armature there is arranged an eleetro-magnet l. The distance separating the said electro-magnet from its armature is regulated by a micron'ieter screw r.

The diaphragm together with its slits is shown in detail in Fig. 2, while the slits are shown separately, partly in section and partly in perspective in Fig. 3, which is drawn to a larger scale.

The mode of operation of the apparatus is as follows :'VVhen telephonic or the like currents are sent through the electromagnet Z and if the apparatus is adjusted so as to be sensitive, the air which passes through the apparatus reproduces, under the influence of the variation of the openings in Specification of Letters Patent.

Patented Mar. 16, 1915.

Serial No. 763,377.

the grating, the sounds which correspond to the currents. lhc.'impi--oved apparatus has not only the important advantage that it has a very loud sound, but that it re produces ibrations, particularly of musical notes, in a perfect manner.

hat I do claim as my invention, and desire. to-secure by Letters Patent pi the United States, is:-

1. In a sound transmitting apparatus the combination of a casing providing an air blast passage, a stationary grate mounted in said casing, a movable grate associated with said stationary grate, and a sound transmitting electro-magnet associated with said movable grate and controlling the operation thereof.

'3. In a sound transmitting apparatus the coinbimition'ot a casing providing an air blast passage, a diaphragm mounted in said casing and having a grate section, a mov able grate mounted on said diaphragm, and a sound transmitting eleetroanagnetassociated with said movable grate and controlling the operation thereof.

In a sound tlallslllittlng apparatus the combil'iation of a casing providing an air blast passage, a diaphragm mounted in said casing and having a grate section, a movable grate having flexible. suspension on said diaphragi'n and disposed immediately adjacent the grate section thereoL'and a sound transmitting electro-imignet for imparting rectilinear vibratory motion to said movable grate.

t. In a sound transmitting apparatusthe combination of av casing providing an air blast passage, a. diaphragm mounted in said casing and having a grate section, a movable grate having tlexible suspension on said diaphragm and disposed immediately adjacent the grate section thereof, and a sound transmitting electro-magnet mounted on the diaphragm and having its armature mounted on the mo 'able grate for imparting rectilinear vibratory motion to said movable grate.

'ln testimony whereof I have hereunto set my hand in presence of two subscribing Wit- 

